In cash trading systems, sensor signals are important input signals for detecting position coordinates and width of bank notes and for triggering the transmission motion of electronic elements, and a number of sensors are distributed in bank note trading system. A control module (referred to as CPU) of the whole trading system often needs to know sensor signals of respective modules in a real-time manner, so as to issue real-time output control instructions based on position and state information on banknotes. In a case that the number of the sensors is large and physical distribution locations of the sensors are different, the whole trading system is divided into a main control CPU (upper) and multiple slave control CPU (lower), to control the modules. How to realize information interaction (real-time) between the master control CPU and the multiple slave control CPUs and to know signal inputs (sharing) of all sensors simultaneously will increase complexity of a system connection and CPU program control.
In the conventional technology, a method as follows is commonly applied: a master control micro control unit (referred to as MCU) and multiple slave control MCUs are used, where each slave control MCU is responsible for collecting sensor signals of modules thereof and controlling signals of electronic elements, and the information interaction between the master control MCU and the slave control MCUs is completely realized in a communicative manner. A communication process is described as follows.
1. The slave control MCU1 sends a command to the master control MCU, requesting to query a sensor signal of the slave control MCU2;
2. The master control MCU sends a command to read the sensor signal of the slave control MCU2;
3. The slave control MCU2 sends the sensor signal to the master control MCU; and
4. The master control MCU sends the sensor signal to the slave master MCU1.
However, in a case that the master control MCU is to send control instructions to multiple slave control MCUs, the master control MCU has to communicate with the slave control MCUs multiple times to realize the information interaction, which increases redundancy information interaction and reduces communication efficiency, and is not applicable to a rapid real-time response scenario.